Michael has been ruled out of Thursday's preseason game in Cincinnati due to a concussion, Mike Chappell of Fox 59 News Indianapolis reports.
Michael had taken advantage of injuries in front of him on the Colts' depth chart, namely to Marlon Mack (hamstring). The momentum continued Thursday, when Michael racked up five carries for 41 yards before his departure. Michael likely has done enough to secure a spot on the 53-man roster along with Jordan Wilkins and Nyheim Hines, but a concussion leaves his next appearance in question.